Preeclampsia

ABSTRACT

The invention provides a method of treating preeclampsia, fetal growth restriction (FGR or IUGR), obesity in pregnancy, post-partum cardiomyopathy (heart failure in mothers), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet microdegeneration and other disorders where angiogenesis is aberrant either diminished or exacerbated, comprising modulating the activity of micro RNA (miRNA). Also provided are an MiRNA modulator or a combination thereof or functional fragments or homologues thereof for use in the treatment of preeclampsia, fetal growth restriction, obesity in pregnancy, cancer, and diabetic retinopathy, cardiomyocyte infarction, wet microdegeneration as well as other disorder where angiogenesis is aberrant either diminished or exacerbated. Methods of modulating angiogenesis and pharmaceutical compositions using miR-122, miR-374b or inhibitors of miR-152 or miR195 are also provided together with methods of diagnosis using the miRNAs.

The invention provides methods of treating preeclampsia by modulating the activity of an miRNA.

INTRODUCTION

Soluble fms-like tyrosine kinase-1 (sFlt-1 or sVEGF-1) is a splice variant of VEGF receptor 1 (Flt-1) and acts as a receptor of vascular endothelial growth factor (VEGF) (Kendall et al., 1996). However, sFlt-1 lacks the transmembrane and cytoplasmic domains of the receptor, and thereby blunts the VEGF signalling pathway by binding to the free circulating VEGF (Wu et al., 2010). The abnormal sFlt-1 expression was identified in many pathological conditions, including different type of cancers, liver cirrhosis, diabetes and peripheral arterial disease (Bando et al., 2005; Ebos et al., 2004; Lamszus et al., 2003; Jaroszewicz et al., 2008; Blann et al., 2002; Findley et al., 2008).

Among these diseases, the role of sFlt-1 is best characterized in the pathogenesis of preeclampsia. Preeclampsia is a maternal medical condition clinically defined as hypertension, proteinuria and renal damage in pregnant women. Currently preeclampsia is the major cause of maternal and perinatal mortality and morbidity (Steegers et al., 2010) and affects 3% to 8% of all pregnancies and women worldwide (Sibai et al., 2005). The pathogenesis of preeclampsia is complex, but it has been suggested that the endothelial dysfunction and resulted abnormal angiogenesis, a process which new blood vessels form from existed ones, in the placenta underlie the clinical manifestation of this medical condition (Hladunewich et al., 2007; Silasi et al., 2010; Maynard et al., 2008). The excessive expression of sFlt-1 in the plasma and placenta of preeclamptic women was identified and the plasma level of sFlt-1 could be used as a potential clinical marker of preeclampsia (Stepan et al., 2007). Moreover, the elevated sFlt-1 was thought to be the main cause of preeclampsia (Maynard et al., 2003; Powe et al., 2011). Our previous data demonstrated that Heme oxygenase 1 (Hmox1), a protective enzyme, negatively regulates sFlt-1 release, whereas the VEGF growth factors promotes sFlt-1 expression (Cudmore et al., 2007; Ahmad et al., 2011). Based on these findings, our and others started pilot trials to use statin, a potent Hmox1 inducer, to prevent the preeclampsia in high risk women (Costantine et al., 2013). However, the molecular mechanism of how Hmox1 or VEGF regulates sFlt-1 is still unknown. MicroRNA is a 21-23-nt small non-coding RNA which binds to 3′-UTR of the mRNA of their target genes with a partially complement manner, and thus leads to the translational repression of target genes (Bartel 2009; Lewis et al., 2003; Williams 2008). Recently, microRNAs are shown to be important in the regulation of many developmental, physiological and pathological processes (Williams 2008; He and Hannon, 2004). Microarray profiling and further quantitative PCR analysis have revealed that microRNAs are differently expressed in the placenta of preeclamptic and normal pregnant women (Pineles et al., 2007; Zhu et al., 2009; Hu et al., 2009; Mayor-Lynn et al., 2011; Enquobahrie et al., 2011; Noack et al., 2011). Furthermore, the interaction of microRNA and Hmox1 in stem cell differentiation, lung carcinoma and oxidant injury was reported (Kozakowska et al., 2014; Skrzypek et al., 2013; Hou et al., 2012). Thus, we hypothesized that Hmox1 may regulate sFlt-1 release via microRNAs and the dysregulation of microRNAs in placenta contributes to the preeclamptic pathogenesis. Utilizing a qPCR based microarray, our present study identified two microRNAs, miR-122 and miR-374b, which can be regulated by hemin, a potent Hmox1 inducer. Furthermore, these microRNAs were demonstrated to be regulated by statin, Hmox1 and VEGF which also regulate sFlt-1 expression. Moreover, sFlt-1 was proved to be the direct target of these microRNAs and the regulation of sFlt-1 by Hmox1 was conducted by these microRNAs. Most importantly, these microRNAs are decreased in the preeclampsia patients and RuPP preeclamptic model. The negative correlation of these microRNAs and blood pressure in animal model was also discovered. Our study provides the novel molecular mechanism of sFlt-1 regulation and these microRNAs may serve as the new therapeutic targets of sFlt-1 related diseases.

MicroRNA-152 is a member of broadly conserved miR-148/152 family. It has been shown to regulate epigenesis by targeting DNMT1 (Xiang et al., 2013; Ji et al., 2013; Huang et al., 2010; Braconi et al., 2010), inhibits cancer cell proliferation and adhesion (Zhou et al., 2012; Mancini et al., 2012) and increases cell cytolysis (Zhu et al., 2010).

Further study confirmed its anti-tumor effect, and hence the down-regulation of miR-152 expression by hypermethylation in various cancer types (Hiroki et al., 2010; Tsuruta et al., 2011; Braconi et al., 2010; Chen et al., 2010; Huang et al., 2010; Wang et al., 2010; Stumpel et al., 2011; Kitano et al., 2011; Zhou et al., 2012). Most importantly, it has been shown to be up-regulated in the placenta of preeclampsia patients (Zhu et al., 2009). Furthermore, miR-152 reduces tumor cell angiogenesis (Zheng et al., 2013; Xu et al., 2013) and down-regulates expression of important pregnancy-related gene (HLA-G) (Manaster et al., 2012). Since miR-152 inhibits cancer cell proliferation and angiogenesis and also implicated in the preeclampsia by microarray profiling, we hypothesized that miR-152 in the preeclampsia regulates endothelial function to contribute to the pathogenesis of preeclampsia. In the current study, we confirmed the up-regulation of miR-152 in the placenta of different gestational placentas, more precisely defined preeclampsia patients as well as in the animal preeclampsia models, demonstrated the increase of miR-152 expression under hypoxia and inflammatory condition. Further study revealed the decrease of PlGF expression, endothelial cell adhesion and angiogenic abilities upon overexpression of miR-152. Moreover, the intraperitoneal injection of virus expressing miR-152 caused devascularization in the placenta and restricted fetal growth. Furthermore, we identified a novel target of miR-152, ITGA5, in both endothelial cells and mouse models and proved the negative correlation of miR-152 and ITGA5 in the preeclampsia patient placental tissue. The identification of miR-152 and its target, ITGA5, in the pathogenesis of preeclampsia will contribute to the understanding of this medical condition and may offer novel therapeutic targets.

MicroRNA-195 is a member of the broadly conserved miR-15/107 super family. It has been shown to be a tumor suppressor and suppresses cancer cell proliferation, migration, invasion and angiogenesis by targeting various downstream factors (Amer et al., 2014; Zhao et al., 2014; Jain et al., 2014; Guo et al., 2014; Wang et al., 2014 a and b; Yang et al., 2014; Luo et al., 2014; Fu et al., 2013; Wang et al., 2013). Furthermore, miR-195 regulates insulin signalling pathway and is implicated in the type 2 diabetes as well as diabetic associated renal injury and retinopathy (Chen et al., 2012; Mortuza et al., 2014; Yang et al., 2014; Ortega et al., 2014; Herrera et al., 2010; Guo et al., 2013). Moreover, miR-195 is also associated with acute myocardial infarction and cardiac hypertrophy by inhibiting cell cycle in cardiomyocytes (Long et al., 2012; You et al., 2014; van Rooij et al., 2006; Busk and Cirera, 2010; Porrello et al., 2011). Interestingly, miR-195 has been recently demonstrated to regulate aortic extracellular matrix and can be used as biomarker for deep vein thrombosis (Zampetaki et al., 2014; Qin et al., 2014). Further studies revealed its role in the pregnancy and associated complications. The expression of miR-195 was significantly up-regulated in third trimester human placentas compared to first trimester (Gu et al., 2013). More importantly, the expression of miR-195 in the preeclamptic placenta is different compare to the normal pregnant placenta, implying the possible role of mir-195 in the pathogenesis of preeclampsia (Xu et al., 2014; Zhu et al., 2009; Hu et al., 2009).

Endothelial nitric oxide synthase (eNOS or NOS3) is an enzyme that breaks down L-arginin to generate nitric oxide (NO) gas in endothelial cells and plays a key role in the vascular endothelium (Huang, 2003). eNOS produces low concentration of NO which offers protection to the endothelial function and integrity and loss of eNOS causes a variety of diseases including preeclampsia (Albrecht et al., 2003; Forstermann and Münzel, 2006; Fatini et al., 2006). Moreover, eNOS/NO has been identified as a key mediator of neocascularization (Duda et al., 2004) and VEGF fails to angiogenesis in eNOS^(−/−) mouse (Lin and Sessa, 2006). However the regulatory mechanisms of eNOS expression are largely unknown. So far, only one microRNA, miR-155, was reported to directly target eNOS in endothelial cells (Sun et al., 2012).

Since miR-195 inhibits cancer cell proliferation and angiogenesis and also implicated in the preeclampsia by microarray profiling, we hypothesized that miR-195 negatively regulates endothelial function to contribute to the pathogenesis of preeclampsia. In the current study, we confirmed the up-regulation of miR-195 in the placenta of different gestational placentas, obesity pregnant women, more precisely defined preeclampsia patients as well as in the animal preeclampsia models, demonstrated the increase of miR-195 expression under inflammatory (or incombination with hypoxia) condition. Further study revealed the decrease of PlGF expression, endothelial cell proliferation, viability, adhesive and angiogenic abilities upon overexpression of miR-195. Furthermore, we identified eNOS as a novel target of miR-195 and overexpression of eNOS^(S1177D) rescued miR-195 mediated suppression of angiogenesis in endothelial cells. Giving the importance of eNOS in the pathogenesis of preeclampsia, the identification of miR-195 will contribute to the current understanding of this medical condition and may offer novel therapeutic targets.

The invention provides a method of treating preeclampsia by modulating the activity of microRNA (miRNA). The activity is typically the function of the miRNA in RNA silencing or post-transcriptional regulation of gene expression of one or more genes involved in preeclampsia, fetal growth restriction (FGR or IUGR), obesity in pregnancy, post-partum cardiomyopathy (heart failure), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet macrodegeneration as well as other disorder where angiogenesis is aberrant either diminished or exacerbated, to reduce the symptoms or and diagnosis of these diseases in a subject, such as a human subject having symptoms of these diseases.

The miRNA is typically selected from one or more miR-122, miR-374b, miR-152 and miR-195 or functional fragments or homologues thereof. For example, one or more of miR-122, miR-374b plus miR-152 or miR-122, miR-374b plus miR-195.

miR-122, miR-374b, miR-152 and miR-195 and inhibitors of them are generally known in the art and indeed are commercially available from, for example, Qiagen Ltd, Manchester, United Kingdom.

They may be:

as-miR-122-5p uggagugugacaaugguguuug has-miR-374b auauaauacaaccugcuaagug has-miR-152-3p ucagugcaugacagaacuugg has-miR-195-5p uagcagcacagaaauauuggc has-miR-122-5p inhibitor caaacaccauugucacacucca has-miR-374b inhibitor cacuuagcagguuguauuauau has-miR-152-3p inhibitor ccaaguucugucaugcacuga has-miR-195-5p inhibitor gccaauauuucugugcugcua

Typically inhibitors are nucleic acid molecules substantially complementary to the miRNA to allow a duplex to form. For example, one or two bases may not be complementary, but still allow duplex formation to occur.

The term “functional fragments” is intended to mean fragments of miRNA (or inhibitors of miRNA) retaining the same biological activity as the native miRNA or its inhibitor. The native miRNA or its inhibitors may also have additional sequences of nucleic acids, such as 1, 2, 3, 5, 10 or 15 nucleic acids added to the 5′ or 3′ end of the miRNA sequence or its complementary sequence as appropriate. To increase the stability or achieve better efficiency, the native miRNA or its inhibitors may be modified chemically, for example pegylated. The activity is typically the ability to treat one or more symptoms of preeclampsia.

The term “homologue” is intended to mean a miRNA having the same activity as the miRNA, such as the regulation of the same gene(s) as the miRNA. For example, it is known that animal miRNAs are able to recognise target mRNAs by using as little as 6-7 nucleotides (the seed region) at the 5′ end of the miRNA. Hence, typically such homologues are typically miRNA having at least 6 to 8, or at least 10 to 12 nucleotides at the 5′ end which are identical to those of the native miRNA. The miRNA may be a miRNA mimic. Such mimics are chemically synthesized dsRNA which mimic endogenous miRNAs after transfection into cells.

The treatment may involve one or more of increasing miR-122, miR-374b, miR-152 or miR-195 activity; or decreasing miR-122, miR-374b, miR-152 or miR-195 activity in the subject with preeclampsia, FGR or IUGR, obesity in pregnancy, post-partum cardiomyopathy (heart failure), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet macrodegeneration as well as other disorder where angiogenesis is aberrant either diminished or exacerbated.

A miRNA activity may be increased by upregulating miRNA production. Alternatively, miRNA, or functional fragments or homologues thereof, may be injected into the organism, for example, into the placenta. Furthermore, the miRNA, or functional fragments or homologues thereof, may be cloned into an expressing plasmid or packed into adenovirus, AAV or Lentivirus and injected into the organism by intravenously (IV), intramuscularly (IM) or subcutaneously (SC) administration.

miRNA may be inhibited by inhibitors of miRNA. For example, single stranded inhibitors of siRNA, such as inhibitors of miR-152 or mirR-195 may be used. Moreover, the inhibitors of miRNA, functional fragments or homologues thereof, may be cloned into an expressing plasmid or packed into adenovirus, AAV or Lentivirus and injected into the organism by intravenously (IV), intramuscularly (IM) or subcutaneously (SC) administration.

The use of miR-122 or miR-374b to modulate angiogenesis is also provided. The miRNA may be, for example, under or overexpressed in cells to study the effect on angiogenesis. This may be used, for example, to model disorder where angiogenesis is aberrant either diminished or exacerbated or, for example, preeclampsia in pregnant women or in post-partum cardiomyopathy in the mother. They may also be used in the treatment of cancers.

Pharmaceutical compositions comprising two or more miR-122, miR-374b, an inhibitor of miR-152 and an inhibitor of miR-195, or functional fragments or homologues, or pharmaceutically acceptable salts thereof. The miRNA may be used as its native form or with a modified form, for example pegylated.

miR-122 and miR374b may be used to inhibit sFlt-1 by introducing the miRNAs into a subject where angiogenesis is aberrant either diminished or exacerbated. They may, for example, be used in cells in vitro or animal models in vivo to modulate sFlt-1 and study the effects of sFlt-1 on the cell or animal model. Furthermore, they may, for example, be used in preeclamptic woman placenta to suppress the sFlt-1 level.

The invention will now be described by way of example only with reference to the following figures:

FIG. 1. Soluble fms-related tyrosine kinase 1 (sFlt-1) is regulated by various compounds and growth factor. (A) HUVEC cells were stimulated with VEGF-A (20 ng/ml) and VEGF-E (20 ng/ml) for 24 hours and the condition media was assayed for sFlt-1. (B) HUVEC cells were treated with 2 uM and 20 uM pravastatin for 24 hours and the conditioned media was assayed for sFlt-1. (C) HUVEC cells were treated with 0.1 uM, 1 uM and 10 uM Hemin under vehicle or VEGF-E stimulation for 24 hours. The conditioned media was collected and assayed for sFlt-1 by ELISA.

FIG. 2. MiR-122 and miR-374b are regulated by various agents that regulate sFlt-1 release. HUVEC cells were treated with 10 uM Hemin (A), 2 uM or 20 uM Pravastatin (B) 20 ng/ml VEGF-A (C) or 20 ng/ml VEGF-E (D) for 24 hours. Total RNA of the treated cells was isolated and the expression of miR-122 and miR-374b was measured by quantitative PCR. The relative miR-122 and miR-374b expression was normalized to RNU6.

FIG. 3. Hmox1 regulates miR-122 and miR-374b expression. HUVEC cells were infected by adenovirus overexpressiong Hmox1 (A) or transfected with siRNA against Hmox1 (B) for 24 hours and the relative expression of miR-122 and miR-374b was measured by qPCR.

FIG. 4. MiR-122 and miR-374b directly regulates sFlt-1 release in endothelial cells. (A) The diagrams show the seed sequence of miR-122 and miR-374b and the according targeting sites in the 3′-UTR of sFlt-1 mRNA. (B) HUVEC cells were electroporated with mimic miR-122 and miR-374b and rested for 24 hours. Transfected cells were then incubated in conditioned media with or without VEGF-E (20 ng/ml) for 24 to 48 hours and the media was assayed for ELISA against sFlt-1. (C) HUVEC cells were electroporated with antagomir of miR-122 and miR-374b and rested for 24 hours. Transfected cells were then incubated in conditioned media with or without pravastatin (20 uM) for 24 hours and the media was assayed for ELISA against sFlt-1. (D) HUVEC cells were electroporated with siHO-1, miR-122 or mi-374b separately or in combination. The transfected cells were then stimulated under vehicle or VEGF-E (20 ng/ml) in conditioned media and assayed for sFlt-1 release by ELISA.

FIG. 5. MiR-122 and miR-374b are decreased both in human severe preeclampsia patients and RuPP mouse model of preeclampsia and negatively correlates with blood pressure in RuPP mice. (A) Placenta samples of term severe preeclampsia patient (N=9-10) and control term pregnant women (N=9-10) have been collected and assayed for relative expression of miR-122 and miR-374b by qPCR. (B) The pregnant Sprague Dawley rats were undergone reduced uterine perfusion pressure (RUPP) surgery and the placenta tissue was collected at term. The expression of microRNA-122 in the placenta of sham control (N=11-12) and RuPP (N=11-12) rats was assayed by quantitative PCR. Data is shown as mean+SEM and analyzed by Student t-test. The relative miR-152 expression was normalized to RNU6. (C) Line graph showing the inverse correlation between mean arterial pressure (MAP) and the expression of miR-122 or miR-374b in the placenta in RuPP mice (N=6). The correlation was calculated by the Pearson's correlation coefficiency (Pearson's correlation r=−0.8101, P=0.05 and r=−0.8451, P=0.034). The relative expression of miR-122 and miR-374b in the placenta of RuPP mice was examined by quantitative.

FIG. 6. Synthetic microRNA-122 and 374b mimic (B, mi-122 and miR-374b) and antagomir (A, anti-122 and anti-374b) were electroporated into HUVEC cells and the relative miR-122 and miR-374b expression was measured by quantitative PCR.

FIG. 7. Inverse correlations between miR-122 or miR-374b expression and systolic or diastolic blood pressure (SBP and DBP) in severe preeclampsia patients. Line graph showing the inverse correlation between SBP or DBP and the expression of miR-122 (A) or miR-374b (B) in the placenta in severe preeclampsia patients (N=8-9). The correlation was calculated by the Pearson's correlation. The relative expression of miR-122 and miR-374b in the placenta of severe preeclampsia patients was examined by quantitative.

FIG. 9. The expression of miR-152 is increased in the placenta of women with severe preeclampsia and animal preeclamptic models. (A) The placenta samples of severe preeclampsia patients (PE, N=14) and the gestation age matched control patients (N=17) were collected and assayed for miR-152 expression using qPCR. (B) The pregnant Sprague Dawley rats were undergone reduced uterine perfusion pressure (RUPP) surgery and the placenta tissue was collected. The expression of microRNA-152 in the placenta of normal pregnant (N.P., N=12) and RuPP (n=17) rats was assayed by quantitative PCR. (C) The pregnant C57BL/6 mice were injected with 109PFU adenovirus, ad-CMV or ad-sFlt-1, at E 9.5 via tail vein injection. The sFlt-1 expression level in the circulation was measured using ELISA against Flt-1 and the mean artery pressure (MAP) was evaluated in the carotid artery at E 17.5 (FIG. 17). Placenta tissue from ad-CMV control virus (N=7) and ad-sFlt-1 virus (N=5) injected mice was collected and assayed for microRNA-152 expression using quantitative PCR. Furthermore, the expression of miR-152 was increased in intrauterine growth restriction (IUGR), obesity pregnant women and diabetic mouse model. (D) The expression of miR-152 in the placenta of IUGR (N=12) as well as in the gestation age matched control patients (N=17). (E, F) The expression of miR-152 in the visceral and subcutaneous fat of pregnant women with BMI over 30 (N=25 and 24 respectively) or with normal BMI (18-25) (N=22 for visceral and 20 for subcutaneous fat) was determined by qPCR. (G, H) miRNA-152 expression in the liver and mesenteric fat of db/db diabetic mouse and control mouse line was measured (N=5). Data is shown as mean+SEM and analyzed by Student t-test. The relative miR-152 expression was normalized to RNU6. *** P<0.001 vs 1^(st) trimester and # # P<0.01 vs 2^(nd) trimester placental samples.

FIG. 10. Hypoxia, inflammatory cytokine or angiogenic growth factor stimulation increases microRNA-152 expression in endothelial cells and placental explants. Human placental explants was treated with (A) inflammatory cytokine mix (TNF-α, 20 ng/ml, IFN-γ, 20 ng/ml and IL-1β, 2 ng/ml), (B) hypoxia (1% O2) condition or (C) combination of cytokine mix and hypoxia condition and assayed for miR-152 expression using qPCR. Similarly, HUEVC cells were treated with (D) hypoxia (1% O2) condition, VEGF-E (20 ng/ml, E) or FGF-2 (20 ng/ml, F) for 24 hours and used for qPCR analysis of miR-152 expression. Moreover, overexpression of miR-152 inhibited PlGF release, but not the sFlt-1 and sEng in endothelial cells. HUVECs were electroporated with mimic-152 or control mimic-con. After resting for 24 hours, the transfected cells were treated with vehicle or VEGF-E (20 ng/ml) in the conditioned media. The media was collected after 24 hours incubation and assayed for the sFlt-1 (G), sEng (H) and PlGF (I) concentration using ELISA. Data is shown as mean+SEM and analyzed by Student t-test.

FIG. 11. Blocking of miR-152 increased endothelial cell viability, but either inhibition or overexpression of miR-152 did not change endothelial cell proliferation or apoptosis. (A) HUVEC cells were electroporated with anti-152 (I) or mimic-152 (II). After overnight recovery, transfected cells were trypsinized and plated into 96-well plate with 1×10⁴ per well under the vehicle or VEGF-A (20 ng/ml) treatment. After 48 hours, these cells were proceeded to MTT assay. (B) For cell proliferation, anti-152 (I) or mimic-152 (II) transfected HUVEC cells were plated in 24-well plate with 4×10⁴ per well density and stimulated with VEGF-A (20 ng/ml) or VGEF-E (20 ng/ml). After 48 hours treatment, cells were trypsinized and the cell number per well was counted under microscope using a hemocytometer. Data is shown as mean+SEM and analyzed by Student t-test. (C) HUVEC cells were transfected with anti-152 (I) or mimic-152 (II) and rested for 24 hours. Cell lysates were blotted with antibody against cleaved caspase 3.

FIG. 12. miR-152 negatively regulates endothelial cell adhesive and angiogenic abilities. (A) HUVEC cells were electroporated with mimic-con or mimic-152 to overexpress miR-152. After 48 hours, 2×10⁴ mimic-152 or mimic-con transfected cells were plated in the laminin (1 mg/ml), gelatin (2% solution) and collagen type I (0.1% solution) coated 96-well plate and treated with VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) for 30 minutes. Thereafter, cells were washed three times with PBS, stained with Calcein AM Fluorescent Dye and proceeded to fluorescent microscopy. Representative images were taken under the ×4 magnification and the number of the adhesive cells per field under the ×4 magnification was counted. Data was collected from at least 5 individual fields and shown as mean+SEM. Moreover, HUEVC cells were electroporated with mimic-152 (B) or anti-152 (C) and rested for 48 hours after transfection. Subsequently, the 1×10⁴ transfected cells were plated on the Matri-gel coated 96-well plate under vehicle, VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) treatment. After incubation for 6-8 hours, the phase contrast images of the tubular-like structure were taken at ×4 magnification and the total tube length per ×4 field was quantified. Data was collected from at least 3-5 individual experiments and shown as mean+SEM.

FIG. 13. Overexpression of miR-152 attenuates revascularization in hind limb ischemia (HLI) mouse model. Male C57Bl/6 mice (3-4 month old) were injected intraterially with ad-CMV or ad-152 then subjected to HLI by surgical excising left femoral artery. (A) The relative expression of miR-152 in the control ad-CMV and ad-152 adenovirus injected gastrocnemius muscle was quantified by qPCR at day 3 (N=4 for both) and day 14 (N=11 for ad-CMV and N=9 for ad-152) after the surgery. (B) Blood flow perfusion was measured by LASER Doppler on plantar aspects of the feet of anesthetized mice. Blood flow recovery at day 0, day 4 and day 7 after surgery was calculated as a ratio of blood flow observed in left ischemic foot compared to right non-ischemic foot. * P<0.05. (C) Blood flow recovery at day 7 was calculated (N=11 for ad-CMV and N=9 for ad-152) and the representative images of blood flow perfusion are shown in right panel. Capillary density at day 14 after surgery was quantified in non-ischemic and ischemic gastrocnemius muscle by histological assessment, by isolectin B4 staining. The representative images (D) and quantification of capillary density (E, N=3 each) at day 14 in non-ischemia and ischemia gastrocnemius muscle were shown. (F) The relative expression of miR-152 in the non-ischemia and ischemia gastrocnemius muscle of ad-CMV injected mice (N=9 each) was measured by qPCR.

FIG. 14. Overexpression of miR-152 reduces fetal body weight and impairs vasculature in placenta of pregnancy mice. Female C57Bl/6 mice (3-4 month old) were injected intraperitoneally with 5×10⁹ PFU ad-CMV or ad-152 at embryonic day 11.5 (E11.5) and the pregnancy was terminated and analyzed at embryonic day 17.5. (A) The expression of miR-152 in the plasma of ad-CMV and ad-152 injected mice was measured by qPCR. (B) The representative graph of foetus from mouse injected with ad-CMV or ad-152 at embryonic day 17.5 (E17.5). (C) The average fetal body weight in the C57Bl/6 mice injected intraperitoneally with ad-CMV (N=5) and ad-152 (N=5) was measured at embryonic day 17.5. (D) The representative graph showing the placentas from ad-CMV and ad-152 intraperitoneally injected mice. (E) Isolectin B4 and DAPI staining of haemotrichorial labyrinth zone in the placentas of mice injected with ad-CMV and ad-152 under the fluorescence microscope at 10× and 20× magnifications.

FIG. 15. MiR-152 directly targets ITGA5. (A) The diagram shows the seed sequence of miR-152 and the according targeting site in the 3′-UTR of ITGA5 mRNA. (B) HUVEC cells were electroporated with anti-152 or mimic-152 and rested for 48 h before treatment. The transfected cells were then stimulated with VEGF-A (20 ng/ml) for 1 h and Western blotted with antibodies against Neuropilin 1 (NRP1), caveolin-2 (CAV-2), fms-related tyrosine kinase 1 (Flt-1) and ITGA5. (C) HEK293 cells were transfected with pmiR-ITGA5 or pmiR-ITGA5M (mutation in the microRNA targeting site) together with mimic-con or mimic-152. The plasmid containing renilla luciferase gene was also transfected as the transfection control. After incubated for overnight, the relative luciferase activity was measured and normalized to the renilla activity. (D) Over-expression of ITGA5 rescued mimic-152 inhibited tube formation. HUEVC cells were infected with adenovirus of ITGA5 for overnight, then electroporated with mi-con or mi-152. After 24-48 hours, cells were trypsinized for Matri-gel tube formation assay. Fluorescence images were taken under phase contrast microscope at ×4 magnification and the total tube length per ×4 field was calculated. The over-expression of ad-ITGA5 was confirmed by western blot using an anti-ITGA5 antibody (insert).

FIG. 16. The ITGA5 expression is inversely correlated with miR-152 levels in mouse models and severe preeclampsia patients. (A) 2×10¹² GC of adeno-associated control virus (AAV-con) or miR-152 AAV virus were injected into adductor muscle of C57BL/6 mice and the muscle samples were collected after 4 weeks and western blotted for ITGA5 and GFP antibodies. The relative ITGA5 expression was calculated as a ratio of ITGA5 expression in AAV-152 injected muscle compared to AAV-con injected muscle (N=4 each). (B) The gastrocnemius muscle samples from Hind limb ischemia were blotted with antibody against ITGA5. The ratio of ITGA5 expression in the ischemic and non-ischemic muscle in ad-CMV (N=11) and ad-152 (N=9) injected mice was calculated. (C) The ITGA5 protein expression in the placenta of mice injected intraperitoneally with ad-CMV (N=4) and ad-152 (N=4) was examined by western blot. (D) The relative expression of miR-152 in the placenta of eight severe preeclampsia patients was examined by quantitative PCR and the corresponding ITGA5 protein expression was also determined by western blot using an anti-ITGA5 antibody. (E) Line graph showing the inverse correlation between the expression of miR-152 and ITGA5 levels in the placentas of severe preeclampsia patients. The correlation was calculated by the Pearson's correlation coefficiency from eight severe preeclampsia patient samples (Pearson's correlation r=−0.823, P=0.0121).

FIG. 17. The sFlt-1 expression and mean artery pressure (MAP) in the ad-sFlt-1 injected mice. The pregnant C57BL/6 mice were injected with 109 PFU adenovirus, ad-CMV or ad-sFlt-1, at E 9.5 via tail vein injection. (A) The sFlt-1 expression level in the plasma was measured using ELISA against Flt-1 in the plasma of ad-CMV (N=6) and ad-sFlt-1 (N=5) injected mice at E 17.5. (B) The mean artery pressure (MAP) was evaluated in the carotid artery in the ad-CMV (N=4) and ad-sFlt-1 (N=5) injected mice at E 17.5.

FIG. 18. Synthetic microRNA-152 antagomir (A, anti-152) and mimic (B, mimic-152) were electroporated into HUVEC cells and the relative miR-152 expression was measured by quantitative PCR.

FIG. 19. MiR-152 positively regulates HUVEC cell migration. HUEVC cells were electroporated with anti-microRNA-152 (A) or mimic-152 (B). After 48 hours recovery, the scratch was made in the centre of the transfected confluent cells in a 12- or 6-well plate. The width of the scratches was measured immediately at 0 and 16-20 hours after the scratches were generated. The cell migration distance was calculated by subtracting the width of scratches at 0 and 16-24 hours. Data was collected from at least 4-5 wells and three random areas from each scratch were measured under microscope.

FIG. 20. (A) The diagram of pMirTarget plasmid used for the microRNA target validation. (B) The expression of red fluorescent protein (RFP) in the HUEVC cells transfected with pmir-ITGA5 plasmid.

FIG. 21. The expression of miR-152 in AAV-152 infected C57BL/6 mouse. 2×10¹² GC of AAV-con or AAV-152 per animal were injected locally into the left side adductor (LAD) muscle and the same volume saline solution was injected into the right side (RAD) as control. After 4 weeks, the adductor muscle from both left and right side was collected and each sample was separated into two parts for qPCR analysis, western blotting and frozen sectioning. (A) The expression of miR-152 in the adductor muscle injected with AAV1-con and AAV1-152 after 4 weeks was assayed by quantitative PCR. (B) The frozen muscle samples of LAD and RAD were cut into 5 uM sections with a cryostat and the images of GFP expression were taken at ×20 magnification using a fluorescence microscope. (C) The representative image of GFP and DAPI overlapping in the LAD muscle.

FIG. 22. The expression of miR-195 is increased in the placenta of women with severe preeclampsia and animal preeclamptic models. (A) Placenta tissue from pregnant women of 1st trimester (N=6), 2nd trimester (N=6) and 3rd trimester (N=4) was collected and measured for relative miR-195 expression by qPCR. Furthermore, the expression of miR-195 in the visceral (B) and subcutaneous fat (C) of pregnant women with BMI over 30 (N=25 and 24 respectively) or with normal BMI (18-25) (N=22 for visceral and 20 for subcutaneous fat) was determined by qPCR. (D) The expression of miR-195 was measured in the placenta of severe preeclampsia (N=14), IUGR (Intrauterine growth restriction, N=12) as well as in the gestation age matched control patients (N=17). (E) The pregnant C57BL/6 mice were injected with 10⁹ PFU adenovirus, ad-CMV or ad-sFlt-1, at E 9.5 via tail vein injection. The sFlt-1 expression level in the circulation was measured using ELISA against Flt-1 and the mean artery pressure (MAP) was evaluated in the carotid artery at E 17.5 (FIG. 26). Placenta tissue from ad-CMV control virus (N=7) and ad-sFlt-1 virus (N=5) injected mice was collected and assayed for miR-195 expression using qPCR. (F) The pregnant Sprague Dawley rats were undergone reduced uterine perfusion pressure (RUPP) surgery and the placenta tissue was collected. The expression of miR-195 in the placenta of normal pregnant (N.P., N=12) and RuPP (n=17) rats was assayed by qPCR. Moreover, inflammatory cytokine mix alone or in combination with hypoxia increases microRNA-195 expression in endothelial cells and placental explants. (G, H) HUEVCs were stimulated with Inflammatory cytokine mix (TNF-α, 20 ng/ml, IFN-γ, 20 ng/ml and IL-1(3, 2 ng/ml) alone or in combination with hypoxia (1% O2) for 12-24 h and the expression of miR-195 was measured by qPCR. (I) Placenta explants were treated with Inflammatory cytokine mix in combination with hypoxia (1% O2) and the expression of miR-195 was measured by qPCR.

FIG. 23. microRNA-195 negatively regulates endothelial cell proliferation, viability, adhesive ability and angiogenesis. (A) HUVECs were electroporated with mi-con or mi-195 and treated under vehicle or VEGF-A (20 ng/ml) for 24 h. Medium supernatant was collected for ELISA assay against PlGF and data was generated from three independent experiments. (B) HUEVCs were transfected with mi-195 and plated in 24-well plate with stimulation of VEGF-A (20 ng/ml) or VGEF-E (20 ng/ml). After 48 h treatment, cells were trypsinized and the cell number per well was counted under microscope using a hemocytometer. (C) HUEVC cells were electroporated with mi-195 and plated into 96-well plate with 1×10⁴ per well under the vehicle or VEGF-A (20 ng/ml) treatment. After 48 h incubation, cells were used for MTT assay. (D) HUVEC cells were electroporated with mi-195 or control mi-con. After 48 h, 2×10⁴ mi-195 or mi-con transfected cells were plated in the 2% gelatin coated 96-well plate and treated with VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) for 30 mins. Subsequently, cells were washed three times with PBS, stained with Calcein AM Fluorescent Dye and proceeded to fluorescent microscopy. The number of the adhesive cells per field under the 10× magnification was counted. Data was collected from at least 5 individual fields. (E) HUEVC cells were electroporated with mi-195 and rested for 48 h. Thereafter, 1×10⁴ transfected cells were plated in the matri-gel coated 96-well plate under vehicle, VEGF-A or VEGF-E treatment. After incubation for 6-8 h, images of the tubular-like structure were taken for quantitative analysis.

FIG. 24. microRNA-195 increases HUVEC cell migration. HUEVC cells were electroporated with antagomir anti-195 (A) or mimic mi-195 (B) and rested for 24-48 h to reach confluence. The scratch was made in the centre of the wells of transfected confluent cells in a 12- or 6-well plate. The width of the scratches was measured immediately at 0 h and 16-24 h after the scratches were generated. The cell migration distance was calculated by subtracting the width of scratches at 0 h and 16-24 h. Data was collected from at least 4-5 wells and three random areas from each scratch were measured under microscope.

FIG. 25. miR-195 directly targets eNOS. (A) The diagram shows the seed sequence of human miR-195 and the according targeting site in the 3′-UTR of eNOS mRNA from different species. (B) HEK293 cells were transfected with pmiR-eNOS or pmiR-eNOSM (mutation in the microRNA targeting site) together with mi-con or mi-195. The plasmid containing renilla luciferase gene was co-transfected as control. After incubated for overnight, the relative luciferase activity was measured and normalized to the renilla control activity. (C) HUVECs were transfected with mi-con or mi-195 and total RNA was isolated for qPCR analysis. The expression of eNOS mRNA was measured using primers against eNOS coding sequence. (D) HUVECs were electroporated with mi-con or mi-195 and recovered for 48 h before treatment. After 48 h, cells were stimulated with VEGF-A (20 ng/ml) for 1 h and Western blotted with anti-phosphor-eNOS and total eNOS antibodies. (E) The relative expression of phosphor-eNOS and total eNOS was quantified using Image J. (F) HUEVCs were infected with ad-195 (MOI=100) and assayed for nitric oxide release using a Sievers NO chemiluminescence analyzer. (G) Overexpression of eNOS rescued mi-195 mediated decrease of tube formation. HUEVCs were infected with adenovirus of ad-eNOS (MOI=50) for overnight and subsequently electroporated with mi-con or mi-195. After 24-48 h, cells were trypsinized for matri-gel tube formation assay. The phase contrast images of the tubular-like structure were taken after incubation for 6-8 hours at ×4 magnification. (H) The total tube length per ×4 field was quantified by Image Pro Plus software. Data was collected from at least 3-5 individual experiments and shown as mean+SEM.

FIG. 26. The sFlt-1 expression and mean artery pressure (MAP) in the ad-sFlt-1 injected mice. The pregnant C57BL/6 mice were injected with 10⁹ PFU adenovirus, ad-CMV or ad-sFlt-1, at E 9.5 via tail vein injection. (A) The sFlt-1 expression level in the plasma was measured using ELISA against Flt-1 in the plasma of ad-CMV (N=6) and ad-sFlt-1 (N=5) injected mice at E 17.5. (B) The mean artery pressure (MAP) was evaluated in the carotid artery in the ad-CMV (N=4) and ad-sFlt-1 (N=5) injected mice at E 17.5. Data is shown as mean+SEM and analyzed by unpaired t-test.

FIG. 27. The expression of miR-195 in HUVECs transfected with synthetic antagomir (anti-195) or mimic (mi-195) of microRNA-195 or infected with adenovirus overexpressing miR-195 (ad-195). (A) The efficiency of synthetic anti-195 and mi-195 was determined by quantitative PCR. Anti-195 significantly reduced, while mi-195 increased microRNA-195 expression in transfected HUVEC cells. (B) HUVECs were infected with ad-195 with a MOI of 100. The expression of miR-195 was measured by real-time quantitative PCR and compared to the control adenovirus infected cells.

FIG. 28. (A) The diagram of pMirTarget plasmid used for the microRNA target validation. (B) The expression of red fluorescent protein (RFP) in the HUEVC cells transfected with pmir-eNOS plasmid.

MIR-122 AND MIR-374B

Methods and Materials:

Reagents and Chemicals

Recombinant growth factors, vascular endothelial growth factor A (VEGF-A), VEGF-E were purchased from RELIATech (Brauschweig, Germany). Hemin and pravastatin were purchase from Sigma-Aldrich (USA). M199 medium was purchased from Invitrogen (Paisley, UK). Quantitative PCR primer against miR-122 and mir-374b, gScript™ microRNA cDNA and Synthesis PerfeCTa® SYBR® Green SuperMix Kit were purchased from Quanta Biosciences.

Human Placental Tissue Collection and Preparation

Institutional Ethics Committee approved the placental tissue collection and written informed consent was obtained. All women were followed prospectively from enrolment until delivery. Human placental tissues were collected from women with pregnancy complicated by preeclampsia (N=14) and Intrauterine growth restriction (IUGR, N=12), and from normotensive pregnant women (N=17). The placental tissues collected were further used for quantitative PCR and western blot. Preeclampsia was defined as blood pressure >140/90 mm Hg on at least two consecutive measurements and maternal proteinuria of at least 300 mg/24 h and IUGR was defined as a foetus with estimated weight below the 10th percentile for its gestational age and abdominal circumference below the 2.5th percentile.

Reduced Uterine Perfusion Pressure (RUPP) Rat Model of Preeclampsia

Placenta samples of RUPP preeclamptic model were a gift from Dr. Fergus McCarthy (Cork University Maternity Hospital, Wilton, Cork, Ireland). The experimental procedure and the characterization of rat undergone RUPP surgery were described previously (McCarthy et al., 2011).

Cell Culture

Human umbilical vein endothelial cells (HUVECs) were isolated and cultured in M199 medium as described previously (Bussolati et al, 2001). Experiments were performed on third or fourth passage HUVEC.

PCR-Based microRNA Microarray

MicroRNA expression profiling in HUVEC cells stimulated with hemin was determined using a qPCR based array system. HUVEC cells were treated with 10 uM Hemin for 24 hours and the total RNA was isolated for Human miFinder RT² miRNA PCR Array (Qiagen, Cat. No. 331211). The PCR procedure and result analysis were performed according to manufacturer's instruction.

miRNA Mimic and Inhibitor Against miR-122 and miR-374b

Chemically synthesized double-stranded microRNA mimic and single-stranded inhibitor against miR-122 (mi-122 and anti-122) and miR-374b (mi-374b and anti-374b) were purchased from Qiagen and the efficiency was tested by Qper (FIG. 6A, B).

HUVECs were trypsinized, and 1×10⁶ cells were electroporated with ≈0.6 ug mimic-122 or mimic-374b, ≈3 ug anti-122 or anti-374 or control molecules using electroporation (Amaxa GmbH, Cologne, Germany) as described previously (Cudmore et al., 2007).

Adenoviral Gene Transfer

The recombinant, replication-deficient adenovirus-encoding rat HO-1 (AdHO-1) was used as described previously (Cudmore et al., 2008).

siRNA Against Hmox1

The siRNA against Hmox1 was described previously (Cudmore et al., 2008).

Real-time Polymerase Chain Reaction

Sample preparation and real-time quantitative PCR was performed as described previously (Cudmore et al., 2007).

Enzyme-Linked Immunosorbent Assay

Enzyme-linked immunosorbent assay (ELISA) kits for human sFlt-1 was obtained from R&D Systems and performed according to the manufacturer's specifications.

microRNA Target Assay

The plasmid containing 3′UTR of sFlt-1, pmiR-Flt1, was ordered from GeneCopoeia (Cat No. HmiT054531-MT01, MD, USA). The firefly luciferase cDNA was fused with 3′UTR of sFlt-1 and the control renilla luciferase gene was driven by CMV promoter in the same plasmid. The mutant plasmids containing miR-122 and miR-374b binding sites, pmiR-Flt1-M1 and pmiR-Flt1-M2, were generated using site directed mutagenesis technique. The binding site of miR-122 was mutated from “TTTGTAGCATTGTCATCACTCCT” to “TTTGTCGACGGATAGAGAAT”. The two binding sites of miR-374b were mutated from “GTCAAAATAGATTATTATAA” to “GTCAAGAGCAAGGCGCA” and from “TACAATATTTGTACTATTATAT” to “TACAATATTTAGACGCGCT”.

For microRNA target assay, HEK293 cells were transfected with pmiR-ITGA5 or pmiR-ITGA5M together with mimic-con or mimic-152. After overnight incubation, the relative firefly luciferase activity was measured and normalized to the renilla activity according to the manufacture's protocol of Dual-Luciferase® Reporter Assay System (E1910, Promega).

microRNA Target Prediction

The direct targets of miR-122 and miR-374b were predicted using online programs, microRNA.org (http://www.microrna.org/microrna/home.do), PicTar (http://pictar.mdc-berlin.de/) and Target Scan (http://www.targetscan.org/).

Statistical Analysis

All data are expressed as mean+S.E.M. Statistical comparisons were performed using Student's t-Test or Mann-Whitney U test. Statistical significance was set at a value of p<0.05.

Results:

Identification of microRNAs Responding to Hemin Stimulation Using Microarray

Our previous study showed that the release of sFlt-1 in endothelial cells can be regulated by vascular endothelial growth factor (VEGF) and heme oxygenase 1 (Hmox1) (Cudmore et al., 2007; Ahmad et al., 2011). However the molecular mechanisms underlie the sFlt-1 regulation is unclear. Thus we hypothesized that microRNAs may be regulated in the downstream of VEGF or Hmox1 and directly target sFlt-1 mRNA translation. The pilot study confirmed our previous observation that VEGF-E significantly induced sFlt-1 release from endothelial cells (FIG. 1A), while statin, the potent Hmox1 inducer, decreased sFlt-1 level at both 2 uM and 20 uM (FIG. 1B). Furthermore another Hmox1 inducer, hemin, decreased sFlt-1 release as expected at 10 uM in endothelial cells and this reduction cannot be recovered by stimulation of VEGF-E, implying VEGF-E and hemin are individual regulators of sFlt-1 (FIG. 1C).

To identify the microRNAs that respond to hemin stimulation, a qPCR-based microarray was performed using RNA samples isolated from hemin treated HUVEC cells. Briefly, HUVEC cells were treated with 10 uM Hemin for 24 hours and the total RNA was isolated for Human miFinder RT2 miRNA PCR Array (Qiagen, Cat. No. 331211). The results were analyzed using the programme provided by manufacture and the differently expressed microRNAs upon Hemin treatment were determined. In summary, there are 24 up-regulated and 26 down-regulated microRNAs have been identified. To further select the microRNAs directly target sFlt-1, the up-regulated microRNAs were analyzed for the possibility of directly targeting sFlt-1 mRNA using online bioinformatic tools, including microRNA.org, PicTar and Target Scan. Finally, 3 microRNAs, miR-122, miR-144 and miR-374b, were predicted to be the ones directly target sFlt-1 and used for further study.

miR-122 and miR-374b Expression was Regulated by VEGF and Hmox1 Inducer

Since miR-122, miR-144 and miR-374b are predicted to be direct regulator of sFlt-1 and VEGF or Hmox1 inducers regulate sFlt-1 release, we tested whether these microRNAs can be regulated by VEGF or Hmox1 inducers. HUVECs were treated with hemin (10 uM), VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) and the expression of these microRNAs was determined by qPCR. Treatment with hemin increased miR-122 and miR-374b expression by 20-fold and 2.7-fold respectively (FIG. 2A), but had no significant effect on miR-144 expression (data not shown). Moreover, both 2 uM and 20 uM pravastatin stimulation significantly induced miR-122 and mir-374b expression by 3-9-fold and 2.7-fold respectively (FIG. 2B). Inversely, decreased miR-122 expression was decreased by 47% and 75% in VEGF-A and VEGF-E stimulation (FIG. 2C, D). The expression of miR-374b was reduced by 20% and 34% respectively upon VEGF-A and VEGF-E treatment (FIG. 2C, D).

Hmox1 Regulates miR-122 and miR-374b Expression

As Hmox1 inducers modulate miR-122 and miR-374b expression, we investigated whether these microRNAs can be regulated directly by Hmox1. HUVEC cells were infected with adenovirus overexpressing Hmox1 and the expression of miR-122 and miR-374b in these cells were quantified by qPCR. As expected, overexpression of Hmox1 increased miR-122 and miR-374 expression by 7.8-fold and 70-fold respectively (FIG. 3A), but the miR-144 expression was not changed. Conversely, HUVEC cells transfected with siRNA against Hmox1 showed decreased expression of miR-122 and miR-374b at 85% and 25% respectively (FIG. 3B).

MiR-122 and miR-374b Directly Target sFlt-1 mRNA

The previous bioinformatic analysis predicted that miR-122 and miR-374b can directly bind to the 3′-untranslated region (UTR) of sFlt-1 mRNA (FIG. 4A). To further confirm that sFlt-1 mRNA is directly targeted by these microRNAs, the luciferase assay using 3′-UTR of sFlt-1 and mimic of miR-122 (mi-122) or miR-374b (mi-374b) was performed. The plasmids containing 3′-UTR of sFlt-1 either with intact sequence or mutated sequence which the miR-122 and miR-374b binding sites have been modified were fused to the firefly luciferase and transfected into HEK293 cells. These cells were also co-transfected with mimic control, mi-122 and mi-374b alone or in combination. The luciferase activity assay revealed that mi-122 and mi-374b transfection significantly suppressed luciferase activity compared to mimic control transfected cells, while this suppression was not observed in the mutant plasmids containing modified microRNA binding sites (FIG. 4A). Interestingly, the combination of mi-122 and mi-374b did not reduce the luciferase activity further than the individual transfection of mi-122 or mi-374b (FIG. 4A). The targeting of sFlt-1 by miR-122 and mir-374b was confirmed additionally by ELISA measuring sFlt-1 in the culture medium of HUVECs transfected with mi-122 and mi-374b alone or in combination. The sFlt-1 level in the medium of HUVECs transfected with mi-122 or mi-374b was reduced around 30% compared to mimic control in the condition of both vehicle and VEGF-E stimulation (FIG. 4B). Reversely, HUVECs transfected with antagomir of miR-122 (anti-122) and miR-374b (anti-374b) released significantly more sFlt-1 into the medium especially in the condition of statin stimulation (FIG. 4C). More importantly, these microRNAs act in the downstream of Hmox1 to target sFlt-1 expression. HUVECs were transfected with siHO-1 in combination with mi-122 or mi-374b and the sFlt-1 release was measured by ELISA. As expected, siHO-1 transfection significantly increased sFlt-1 expression, while co-transfection with mi-122 or mi-374b completely abolished this increase mediated by siHO-1 (FIG. 4D).

Implication of miR-122 and miR-374b in the Pathogenesis of Preeclampsia

Since the angiogenic imbalance is the main cause of preeclampsia and sFlt-1 antagonists VEGF signalling pathway (Levine et al., 2004; Venkatesha et al., 2006; Ramma and Ahmed, 2011), we measured the expression of miR-122 and miR-374b by qPCR in the placenta of preeclamptic patients and RuPP preeclampsia mouse model. The expression of miR-122 and miR-374b in the preeclamptic placenta was decreased by around 60% and 45% respectively compared to age matched controls (FIG. 5A). Furthermore, their expression in the placenta of RuPP mice was decreased by about 81% and 64% respectively compared to sham control (FIG. 5B). More importantly, the expression of miR-122 and miR-374b was negatively correlated with the blood pressure in the RuPP mice (FIG. 5C, N=6, R=−0.81 and R=−0.845 respectively) and ad-sFlt-1 virus injected mouse model (FIG. 8, N=5, R=−0.9778 and R=−0.9397 respectively). Moreover, this correlation has been further confirmed in the severe preeclampsia patient. The expression of miR-122 and miR-374b in the placenta of severe preeclampsia patient was negatively correlated with their systolic and diastolic blood pressure (SBP and DBP) (FIG. 7, N=8-9).

miR-152

Methods and Materials:

Reagents and Antibodies

Recombinant growth factors, vascular endothelial growth factor A (VEGF-A), VEGF-E, tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and interleukin 1 beta (IL-1(3) were purchased from RELIATech (Brauschweig, Germany). Rabbit antibody against ITGA5, Caspase 3, Flt-1, CAV2 and NRP1 were obtained from Cell Signaling Technology (Danvers, Mass. 01923, United States). Mouse anti-β-Actin antibody and rabbit anti-GAPDH were obtained from Sigma-Aldrich (A5441, St. Louis, Mo., United States) and Santa Cruze Biotech respectively. Quantitative PCR primer against miR-152, gScript™ microRNA cDNA and Synthesis PerfeCTa® SYBR® Green SuperMix Kit were purchased from Quanta Biosciences. Growth factor reduced Matrigel purchased from Becton Dickinson (Oxford, UK). M199 medium was purchased from Invitrogen (Paisley, UK). Calcein AM Fluorescent Dye was purchased from BD Bioscience (P.O. Box 999 Sparks, Md., USA 21152). DyLight 594 labelled Lycopersicon Esculentum (Tomato) Lectin (LEL, TL) was purchased from Vector Laboratories (Burlingame, Calif. 94010). Alexa Fluor® 594 Conjugated Isolectin GS-IB4 was purchased from Life Technologies (Paisley, UK). OCT compound was purchased from VWR International Ltd. (Leicestershire, LE17 4XN, England).

Human Placental Tissue Collection and Preparation

Institutional Ethics Committee approved the placental tissue collection and written informed consent was obtained. All women were followed prospectively from enrolment until delivery. Human placental tissues were collected from women with pregnancy complicated by preeclampsia (N=14) and Intrauterine growth restriction (IUGR, N=11), and from normotensive pregnant women (N=17). The placental tissues collected were further used for quantitative PCR and western blot. Preeclampsia was defined as blood pressure >140/90 mm Hg on at least two consecutive measurements and maternal proteinuria of at least 300 mg/24 h and IUGR was defined as a foetus with estimated weight below the 10th percentile for its gestational age and abdominal circumference below the 2.5th percentile.

Cell and Placental Explants Culture

Human umbilical vein endothelial cells (HUVECs) were isolated and cultured in M199 medium as described previously (Bussolati et al, 2001). Experiments were performed on third or fourth passage HUVEC. First trimester placental tissues (6-9 weeks gestational age) were retrieved from normal pregnancies that had undergone elective termination. Placental villus tissue explants were prepared as described previously (Ahmad and Ahmed, 2004). Briefly, human placental villus explants were incubated under stimulation of test substances or hypoxia condition and collected for quantitative PCR of miR-152. To create hypoxic condition, 70-80% confluent HUEVCs or placental explants were cultured in an incubator with 1% O₂ and 5% CO₂ at 37° C.

miRNA Mimic and Inhibitor Against miR-152

Chemically synthesized double-stranded microRNA mimic and single-stranded inhibitor against miR-152 (mimic-152 and anti-152) were purchased from Qiagen.

HUVECs were trypsinized, and 1×10⁶ cells were electroporated with ≈0.6 ug mimic-152, ≈3 ug anti-152 or control molecules using electroporation (Amaxa GmbH, Cologne, Germany) as described previously (Cudmore et al., 2007).

Adenovirus and Adeno-Associated Virus Animal Injection

Adenovirus, ad-sFlt-1, was a gift from Prof. Richard Mulligan (Harvard Medical School, Boston, USA). The ad-sFlt-1 and ad-CMV control virus were amplified and titered and 10⁹ PFU adenoviruses were injected into C57BL/6 mice at E 9.5 via tail vein to over-express sFlt-1.

Adeno-associated virus (serotype 1) over-expressing miR-152 (AAV-152) was generated and titered by Vector Biolabs (Philadelphia, USA). The GFP was fused with miR-152 cDNA as reporter gene. In the hind limb muscle injection, 2×10¹² GC of AAV1-con or AAV1-152 AAVs were injected locally into left side adductor muscle of C57BL/6 mice and the same volume saline solution was injected into the right side as control. The virus infection was confirmed by co-expressed GFP reporter protein and over-expression of miR-152 was determined in the muscle 4 weeks after injection by quantitative PCR (FIG. 21).

Reduced Uterine Perfusion Pressure (RUPP) Rat Model of Preeclampsia

Placenta samples of RUPP preeclamptic model were a gift from Dr. Fergus McCarthy (Cork University Maternity Hospital, Wilton, Cork, Ireland). The experimental procedure and the characterization of rat undergone RUPP surgery were described previously (McCarthy et al., 2011).

Real-Time Polymerase Chain Reaction

Sample preparation and real-time quantitative PCR was performed as described previously (Cudmore et al., 2007).

Western Blotting

Total protein from HUVECs or animal tissue was lysed in RIPA buffer and assayed as previously described (Ahmad and Ahmed, 2004).

Enzyme-Linked Immunosorbent Assay

Enzyme-linked immunosorbent assay (ELISA) kits for human sFlt-1, sEng and PlGF were obtained from R&D Systems and performed according to the manufacturer's specifications.

In Vitro Cell Adhesion Assay

HUVECs were electroporated with mimic-152 or control mimic-con. After 48 h, 2×10⁴ mimic-152 or mimic-con transfected cells were plated in the 2% gelatin coated 96-well plate and treated with VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) for 30 mins. Thereafter, cells were washed three times with PBS, stained with Calcein AM Fluorescent Dye and proceeded to fluorescent microscopy. The number of the adhesive cells per field under the 4× magnification was counted.

In Vitro Tube Formation Assay

Formation of capillary-like structures of mimic-152, anti-152 or mimic-152 and ad-ITGA5 treated HUEVCs on growth factor reduced Matrigel was determined as previously described (Bussolati et al, 2001).

In Vitro Cell Viability and Proliferation Assay

HUVEC cells were electroporated with anti-152 or mimic-152. After overnight recovery, transfected cells were trypsinized and plated into 96-well plate with 1×10⁴ per well under the vehicle or VEGF-A (20 ng/ml) treatment. After 48 h, these cells were proceeded to MTT assay using cell growth determination kit (CDG1, Sigma-Aldrich). For cell proliferation assay, transfected cells were plated in 24-well plate with 4×10⁴ per well and stimulated with VEGF-A (20 ng/ml) or VGEF-E (20 ng/ml). After 48 h treatment, cells were trypsinized and the cell number per well was counted under microscope using a hemocytometer.

In Vitro Cell Migration Assay

HUEVC cells were electroporated with anti-152 or mimic-152. After overnight recovery, the scratch was made in the centre of the transfected confluent cells in a 12- or 6-well plate. The width of the scratches was measured immediately at 0 h and 16-24 h after the scratches were generated. The cell migration distance was calculated by subtracting the width of scratches at 0 h and 16-24 h.

Hind Limb Ischemia Mouse Model

Animal study protocols were approved by Aston University Ethical Review Committee and conducted in accordance with the United Kingdom Animals (Scientific Procedures) Act, 1986. Male C57Bl/6 mice (3-4 month old) were injected intraterially with ad-152 or ad-CMV then subjected to HLI by surgical excising left femoral artery as previously described (Murdoch et al., 2014). The left femoral artery was isolated. A temporary proximal ligation of both vein and artery was placed on before canulation and injection of ad-152 or ad-CMV into the left femoral artery. After 5 minutes two further ligations were added just to the artery at a proximal and distal location before excising approximately 1.5 mm. The temporary ligation to the vein was removed. Blood flow perfusion was measured by LASER Doppler (Moor Instruments UK) on plantar aspects of the feet of anesthetized mice (ketamine (100 mg/kg) xylazine (10 mg/kg); i.p.) as previously described (Murdoch et al., 2014). Blood flow recovery was calculated as a ratio of blood flow observed in left ischemic foot compared to right non-ischemic foot. Capillary density was quantified in non-ischemic and ischemic gastrocnemius muscle by histological assessment, by Isolectin B4 staining.

Mouse Pregnancy Study

Three to four month old C57BL/6 mice were mated. The first day of pregnancy (E0.5) was defined by the presence of a vaginal plug the following morning. Pregnant mice were randomly assigned into two groups at day E11.5 and injected intraperitoneally with ad-152 or ad-CMV with a dose of 5×10⁹ PFU per mouse. After 6 days, the pregnant mice were mice were anesthetized using a Ketamine/Xylazine cocktail and subsequently sacrificed for sampling. The live foetuses and placentas were counted and weighed. Their blood was taken and kidneys, livers, spleens and placentas were collected. The expression of miR-152 was measured by qPCR in blood and placentas. The placental tissue was later stained with Isolectin B4 for analyzing of the placental vasculature.

microRNA Target Assay

The Homo sapiens cDNA containing untranslated region (UTR) of ITGA5 was purchased from Origene (Rockville, Md. 20850, USA) and the UTR region was subcloned into pMirTarget to generate ITGA5-UTR-Luciferase (firefly) expression plasmid, pmiR-ITGA5. The successful transfection of pmiR-ITGA5 in endothelial cells was validated by the expression of red fluorescent protein (RFP) (FIG. 21). The plasmid harbouring mutant on miR-152 and ITGA5-UTR binding site was generated using site-directed mutagenesis kit (Stratagene) with PCR primers containing the mutant site and the resulted plasmid was designated as pmiR-ITGA5M. The primers used for PCR amplification were mITGA5-F, TCCCTCCCCCCCATGCTGTGG, and mITGA5-R, TGTAAACAAGGGTCCACAGCA. For microRNA target assay, HEK293 cells were transfected with pmiR-ITGA5 or pmiR-ITGA5M together with mimic-con or mimic-152. The plasmid containing renilla luciferase gene was also transfected as the internal control. After overnight incubation, the relative firefly luciferase activity was measured and normalized to the renilla activity according to the manufacture's protocol of Dual-Luciferase® Reporter Assay System (E1910, Promega).

microRNA Target Prediction

The direct targets of miR-152 were predicted using online programs, microRNA.org (http://www.microrna.org/microrna/home.do), PicTar (http://pictar.mdc-berlin.de/) and Target Scan (http://www.targetscan.org/).

MicroArray Profiling

HUVEC cells were transfected with mimic-152 and the total RNA sample was collected for whole genome gene array analysis using Affymetrix genechip Human Gene 1.0 ST. The up-regulated and down-regulated genes upon mimic-152 transfection are selected using a ±1.25-fold cut off.

Statistical Analysis

All data are expressed as mean+S.E.M. Statistical comparisons were performed using Student's t-Test or Mann-Whitney U test. Statistical significance was set at a value of p<0.05.

Results:

Placental miR-152 Expression is Increased in Preeclampsia Patient and Animal Models, IUGR, Obesity Pregnant Women and Diabetic Mouse Model

Although Zhu and colleagues demonstrated the elevated expression of miR-152 in preeclampsia (Zhu et al., 2009), the placental samples used in their study were collected from preeclampsia women with an average gestational age of 35.9 weeks. To investigate the miR-152 expression in more precisely defined severe preeclampsia patient, the placental samples from preeclampsia women with an average gestational age of 29.7 weeks were collected and examined for miR-152 expression by quantitative PCR. Quantitative PCR revealed that miR-152 in the preeclamptic placenta (N=14) was significantly increased compared to gestation age matched control normotensive placenta (N=17), but not changed in IUGR placenta (N=11), implying miR-152 is up-regulated specifically in preeclampsia (FIG. 9 A).

To further confirm the up-regulation of miR-152 in preeclampsia, the expression of miR-152 was examined in two animal models of preeclampsia. The pregnant mice receiving ad-sFlt-1 adenovirus injection exhibited significant increased placental miR-152 level (FIG. 9 B) as well as elevated sFlt-1 expression and mean artery pressure compared to ad-CMV control virus injected mice (FIG. 17). Moreover, the miR-152 expression in placenta of pregnant Sprague Dawley rats that undergone reduced uterine perfusion pressure surgery (N=17) was also significantly increased compared to normal pregnant rat (N=12, FIG. 9 C), suggesting that miR-152 elevation is associated with pathogenesis of preeclampsia. Severe preeclampsia patients are normally associated with fetal growth restriction (IUGR), thus we examined the miR-152 level in IUGR patient placentas. The expression of miR-152 in the IUGR patients (N=11) was increased by 88% compared to the gestational age-matched controls (N=17, FIG. 9D).

Since obesity pregnant women pose a high risk to preeclampsia, we examined the miR-152 expression in the adipose tissues of obesity pregnant women. As expected, miR-152 expression in the visceral (N=25) and subcutaneous fat (N=24) of obesity pregnant women was increased significantly compared to lean pregnant women (N=20-22) (FIGS. 9E and F). Moreover, we tested the miR-152 level in liver and mesenteric fat of the diabetic db/db mouse. The results confirmed the significant elevation of miR-152 expression in db/db mice compared to controls (N=5, FIGS. 9 G and H).

Hypoxia, Inflammation and Growth Factors Elevated miR-152 Expression

Preeclamptic placenta is associated with hypoxia, inflammation condition as well as the elevation of VEGF and FGF-2 growth factors (Hunter et al., 2000; Ozkan et al., 2008), thus the miR-152 expression in the placental explants and endothelial cells under hypoxia, inflammation and VEGF stimulation was determined by qPCR. Stimulation of mixed inflammatory cytokines in placental explants increased miR-152 by approximate 55% (FIG. 10 A). Furthermore, hypoxia treatment increased miR-152 expression by 75% and 84% in placental explants (FIG. 10 B) and endothelial cells (FIG. 10 D) respectively. The combination of hypoxia and inflammatory cytokine mixture stimulation increased miR-152 expression by 87% in placental explants (FIG. 10 C). Moreover, VEGF and FGF-2 stimulation elevated miR-152 expression by approximately 100% and 65% respectively (FIGS. 10 E and F). These data confirmed that miR-152 is regulated by the pathological conditions in preeclamptic placenta.

MiR-152 Modulates PlGF Expression in Endothelial Cells

The release of anti-angiogenic factors, sFlt-1 and sEng, and the inhibition of placental growth factor expression are the main cause of preeclampsia (Powe et al., 2011; Ahmad and Ahmed, 2004). Moreover, VEGF and inflammatory cytokines stimulation increases sFlt-1 and sEng release (Cudmore et al., 2008), therefore we examined whether miR-152 modulates sFlt-1, sEng or PlGF expression in endothelial cells. HUVECs were transfected with mimic-152 to over-express miR-152 (FIG. 18) and the sFlt-1, sEng and PlGF levels were examined by ELISA. Overexpression of miR-152 in HUVECs decreased PlGF expression under both vehicle and VEGF-E stimulation (FIG. 10 I). Although the expression of sFlt-1 (FIG. 10 G) and sEng (FIG. 10 H) was unaltered, the PlGF level was significantly reduced, thus the ratio of sFlt-1/PlGF was increased. These data further support the concept that miR-152 upregulation may contribute to the pathogenesis of preeclampsia.

MiR-152 has No Effect on Cell Proliferation

Since endothelium dysfunction is the main cause of preeclampsia, we tested whether miR-152 modulates endothelial cell functions. HUVEC cells were transfected with either synthetic inhibitor (anti-152) (I) or the mimic of miR-152 (mimic-152) (II) and the MTT (FIG. 11 A) or cell proliferation assay (FIG. 11 B) was performed. Although anti-152 significantly increased cell viability in HUVECs, the mimic-15 did not change the cell viability under vehicle or VEGF-A stimulation (FIG. 11 A). Moreover, cell proliferation assay confirmed that either anti- or mimic-152 had no effect on HUEVC cell proliferation (FIG. 11 B). Furthermore, western blot analysis revealed that the expression of cleaved Caspase-3 in HUVECs transfected with anti- or mimic-152 was not changed (FIG. 11 C).

MiR-152 Inhibits Endothelial Cell Adhesion and In Vitro Endothelial Cell Tube Formation, but Promotes Cell Migration

The effects of miR-152 in endothelial cell adhesion, migration and angiogenesis were further tested. HUVEC cell adhesive ability was dramatically decreased in the mimic-152 transfected cells regardless the stimulation of VEGF-A and VEGF-E. Cell counting confirmed an 84% reduction of the numbers of adhesive cells in the mimic-152 transfected HUVECs under vehicle condition, while approximate 89% reduction under VEGF-A and VEGF-E stimulation compared to mimic-con transfected HUVECs (FIG. 12 A).

Since miR-152 inhibits angiogenesis in tumor cells, we speculated that miR-152 also inhibits angiogenesis in placental endothelial cells to contribute to the pathogenesis of preeclampsia. HUVEC cells transfected with mimic-152 exhibited decreased tube formation on Matrigel under vehicle, VEGF-A or VEGF-E stimulation (FIG. 12 B). Quantitative analysis revealed a 37% reduction in the tube formation of mimic-152 transfected cells under vehicle condition and 34% to 66% reduction under VEGF-A and VEGF-E stimulation. Conversely, anti-152 transfection increased tube formation in the HUVEC cells by approximate 33% under VEGF-A stimulation (FIG. 12 C). These data confirmed that miR-152 negatively modulates placental endothelial cell in vitro angiogenic ability.

Furthermore, the scratch assay revealed that overexpression of miR-152 increased (FIG. 19 A) while inhibition of miR-152 significantly decreased (FIG. 19 B) HUVEC cell migration ability under vehicle or growth factor stimulation.

Overexpression of miR-152 Impaired Blood Recovery and Revascularization in Hind Limb Ischemia Model

To further test the anti-angiogenic property of miR-152 in vivo, mouse hind limb ischemia model was utilized. Adenovirus overexpressing miR-152 was injected into the femoral artery which was later been removed. The expression of miR-152 in the Gastrocnemius muscle was increased approximate 18-fold on day 3 and 55% on day 14 compared to non-ischemic muscle (FIG. 13 A). Hind limb ischemic blood flow recovery was compared in ad-152 injected mice to ad-CMV injected controls. Blood flow was assessed serially after HLI surgery (days 0, 3, 7, and 14) by LASER Doppler in the plantar aspect of the paws (FIG. 13 C). The blood flow recovery was evidenced in ad-CMV injected mice on day 3 and the ad-152 injected mice exhibited consistent lower blood flow at day 3 and day 7 (FIG. 13 B). At day 7, the blood flow in ad-152 injected mice showed a maximum reduction of approximate 30% compared to controls (FIG. 13 C). Since blood flow recovery relates to the increased tissue capillary density, we examined the capillary density in gastrocnemius muscle (FIG. 13 D). As expected, capillary density was increased in the ischemic gastrocnemius muscle of both ad-152 and ad-CMV injected mice; however in the ischemic ad-152 injected muscle, there was a marked reduction of the capillary increase (FIG. 13 E). Moreover, in agreement with the in vitro observation, the expression of miR-152 in the ischemic muscle of control mice was significantly increased compared to control non-ischemic muscle (FIG. 13 F).

Overexpression of miR-152 Impaired Placental Vasculature in Pregnant Mouse and Inhibited Fetal Growth

To investigate the effect of miR-152 overexpression in pregnancy, the adenovirus overexpressing miR-152 was injected intraperitoneally into pregnant mice at E11.5. After six days of injection, the blood from ad-CMV and ad-152 injected mice was taken and the expression of miR-152 was measured by qPCR. The ad-152 injection significantly increased miR-152 expression compared to ad-CMV control (FIG. 14 A). In line with these data, the fetal growth in the ad-152 injected pregnant mice was significantly restricted (FIG. 14 B). This observation was further confirmed by the measurement of average fetal weight in these mice. The foetuses from ad-152 injected mice exhibited around 25% reduction in body weight compared to the ad-CMV injected mice (FIG. 14 C).

More importantly, the fetal growth restriction could be caused by the impaired neovasculature in the placenta as evidenced by the avasculated placenta in the ad-152 injected mice (FIG. 14 D). Histological analysis of placental labyrinth zones further confirmed this observation. The labyrinth zone consists of cells of trophoblast and fetal endothelial cells, forming a large surface area for nutrient and gas exchange between the mother and foetus. Using isolectin B4 to highlight the fetal endothelial cells, the anatomical features of labyrinth zone in ad-152 and ad-CMV injected mice were analyzed. The vasculature in the labyrinth zone of control mice was well organized with high density of fetal vascular branching. However, the vascular structure in the ad-152 injected labyrinth was observed as irregular branching with much lower density (FIG. 14 E).

MiR-152 Directly Targets ITGA5 in Endothelial Cells

To identify the direct targets of miR-152, gene expression microarray was performed using RNA samples from mimic-152 and mimic-con transfected HUVEC cells. The 14 up-regulated and 34 down-regulated genes upon miR-152 over-expression were selected with ±1.25-fold cut off. These expression altered genes have broad functions on vascular remodelling, cell adhesion, angiogenesis, cell mobility and survival. Moreover, the down-regulated genes were further analyzed using online prediction tools, microRNA.org, PicTar and Target Scan, to confirm the possible direct targets of miR-152 by sequence alignment. Finally, 18 out of 34 down-regulated genes were selected for candidates of miR-152 direct target and the expression of some of these candidate targets were further tested by western blot in HUVEC cells (FIG. 15 B).

Among the targets tested, ITGA5 was the one most regulated by miR-152. ITGA 5 was predicted to be miR-152 direct target by the online prediction tools (FIG. 15 A) and also confirmed by western blot that miR-152 overexpression decreased while inhibition of miR-152 increased ITGA5 expression in HUVECs (FIG. 15 B). MicroRNA target assay further proved that transfection of mimic-152 significantly inhibited luciferase activity in the pmiR-ITGA5 transfected HEK293 cells, but not in the mutant pmiR-ITGA5M transfected cells (FIG. 15 C; FIG. 20). To validate that miR-152 target ITGA5 to fulfil its role on endothelial dysfunction, we tested whether overexpression of ITGA5 could rescue the mimic-152 mediated inhibition of angiogenesis. As expected, overexpression of ITGA5 increased spontaneously tube formation and significantly recovered mimic-152 inhibited tube-like structure in HUVEC cells (FIG. 15 D).

MiR-152 Targets ITGA5 In Vivo and Correlates with ITGA5 in Severe Preeclampsia Patients

More importantly, the regulation of ITGA5 by miR-152 was also confirmed in animal models used in this study. AAV-152 virus injection mediated overexpression of miR-152 (FIG. 21) in the muscle of mouse limb significantly decreased ITGA5 expression compared to control AAV virus injected limb muscle (FIG. 16 A). Furthermore, in hind limb ischemia condition, the ITGA5 expression in the ischemic muscle of mice injected with ad-152 was decreased compared to ad-CMV injected ischemic muscle (FIG. 16 B). Moreover, the ITGA5 expression in the placenta of ad-152 injected pregnant mice decreased dramatically compared to ad-CMV injected placenta (FIG. 16 C).

Since miR-152 is up-regulated in preeclampsia patients and ITGA5 is identified to be the direct target of miR-152, we speculate that the expression of miR-152 and ITGA5 in the preeclampsia patients was negatively correlated. The expression of miR-152 and ITGA5 was examined from 8 preeclampsia and 8 gestational age matched control patients using qPCR and western blot respectively (FIG. 16 D). The negative correlation of miR-152 and ITGA5 expression was found in the preeclamptic placentas (R=−0.823, FIG. 16 E), but not in the control normotensive placentas, suggesting miR-152 targets ITGA5 specifically in the pathological condition of preeclampsia.

DISCUSSION

MiR-152 in Preeclampsia

Although microarray profiling and next generation sequencing techniques revealed that microRNAs are differently expressed in the placenta of preeclamptic women (Yang et al., 2011; Wu et al., 2012; Hromadnikova et al., 2012; Pan et al., 2012), only very limited number of microRNAs have been characterized for their roles in preeclampsia pathogenesis, especially in the dysfunction of endothelium. Mir-152 expression has been shown to be up-regulated in the placenta of preeclampsia patients by microarray profiling (Zhu et al., 2009).

In line with this, our data confirmed the elevated expression of miR-152 in a more precisely defined population of severe preeclampsia patients with an average gestational age of 29.7 weeks. Moreover, we proved the up-regulated miR-152 expression in the mouse and rat models of preeclampsia, further strengthened the possibility that miR-152 is associated with preeclamptic pathogenesis.

The preeclamptic placenta is associated with hypoxia and inflammatory conditions (Lockwood et al., 2008; Soleymanlou et al., 2005). Our data demonstrated that hypoxia and inflammatory cytokines increased miR-152 expression in placental explants suggesting miR-152 could be the molecular clue to understand the pathogenesis of preeclampsia. In addition, the imbalance of angiogenesis has been highlighted as the primary culprit in preeclampsia (Ramma and Ahmed, 2011; Ramma et al., 2012). In our study, miR-152 was identified to be a negative regulator of PlGF, an important growth factor for placental function, in endothelial cells. Although sFlt-1 and sEng levels were not changed by overexpression of miR-152, the sFlt-1/PlGF ratio was increased due to the decreased level of PlGF. Since the elevated sFlt-1/PlGF ratio is an important indicator of angiogenic imbalance and a reliable biomarker in the assessment of preeclampsia (De Vivo et al., 2008; Verlohren et al., 2012), the elevated miR-152 expression in the preeclamptic placenta may contribute to the angiogenic dysfunction in preeclampsia pathogenesis.

MiR-152 Modulates Endothelial Functions Via ITGA5

Mir-152 has been shown to inhibit cell proliferation and adhesion (Zhou et al., 2012; Mancini et al., 2012) as well as tumor cell angiogenesis (Zheng et al., 2013; Xu et al., 2013), but not in the endothelial cells. Our data demonstrated that miR-152 decreased endothelial cell adhesive and angiogenic abilities, and increased cell migration, but had no effect on cell proliferation. Endothelial dysfunction plays a central role in the pathogenesis of preeclampsia and causes most clinical symptoms of preeclampsia (Poston 2006; Baumwell and Karumanchi, 2007), thus miR-152 may contribute to the pathogenesis of preeclampsia by modulation of endothelial functions.

ITGA5 belongs to the integrin alpha chain family which promotes cell adhesion, invasion and migration in cancer cells (Hood and Cheresh, 2002; Wang et al., 2008; Qin et al., 2011). Moreover, it has been shown to promote vasculogenesis and angiogenesis in endothelial cells and mouse embryo (Francis et al., 2002; Bonauer et al., 2009). In our study, ITGA5 was found to be the direct target of miR-152 and also the mediator of miR-152 induced endothelial dysfunction. By directly targeting ITGA5, miR-152 inhibited endothelial cell adhesion and the reduced cell adhesion subsequently led to the promoted cell migration (Moh and Shen, 2009; Grzesiak et al., 2005). More importantly, overexpression of ITGA5 rescued the mimic-152 inhibited angiogenesis in endothelial cells suggesting that ITGA5 is the downstream effector of miR-152 mediated endothelial dysfunction at least on the disruption of angiogenesis. Notably, our microarray data revealed more possible targets of miR-152 which regulate vascular remodelling, cell adhesion, angiogenesis, cell mobility and survival processes. These potential targets of miR-152 may further contribute to the different clinical manifestation of preeclampsia.

MiR-152 for Preeclampsia Therapy

Since effective treatment to preeclampsia is not currently available, the early prediction of high-risk women is important for the prevention and primary care of this medical condition (Leslie et al., 2011). Moreover, a recent meta-analysis suggests that low-dose aspirin started before 16 weeks' gestation could prevent up to 50% of PE, severe PE, and intrauterine growth restriction (IUGR) in high-risk women (Bujold et al., 2009). Thus a biomarker that accurately predicts preeclampsia is of great clinical value. Recently, miR-152 has been implicated in the serum of pregnant women and suggested for the potential use as biomarker (Williams et al., 2013). Based on our current study that miR-152 elevated in severe preeclampsia, miR-152 expression in the serum of early pregnancy of preeclampsia high-risk women should be examined to validate its biomarker potential.

Preeclampsia is a multifactorial disease which causes maternal and fetal morbidity and mortality worldwide (Pennington et al., 2012), thus there is a pressing need for novel approaches to tackle this complex medical condition. Our data revealed that miR-152 is elevated in the preeclampsia and subsequently leads to the endothelial dysfunction via targeting ITGA5 suggesting that miR-152 and ITGA5 may serve as potential therapeutic targets in preeclampsia. More importantly, the miR-152 and ITGA5 expression in the placenta of preeclamptic women was negatively correlated, further confirming the therapeutic potential of miR-152 and ITGA5 in preeclampsia.

miR-195

Methods and Materials:

Reagents and Antibodies

Recombinant growth factors, vascular endothelial growth factor A (VEGF-A), VEGF-E, tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and interleukin 1 beta (IL-1β) were purchased from RELIATech (Brauschweig, Germany). Rabbit antibody against total eNOS and phosphor-eNOS were obtained from Cell Signaling Technology (Danvers, Mass. 01923, United States). Mouse anti-β-Actin antibody was obtained from Sigma-Aldrich (A5441, St. Louis, Mo., United States). Quantitative PCR primer against miR-195, gScript™ microRNA cDNA and Synthesis PerfeCTa® SYBR® Green SuperMix Kit were purchased from Quanta Biosciences. Growth factor reduced Matrigel purchased from Becton Dickinson (Oxford, UK). M199 medium was purchased from Invitrogen (Paisley, UK). Calcein AM Fluorescent Dye was purchased from BD Bioscience (P.O. Box 999 Sparks, Md., USA 21152).

Human Placental Tissue Collection and Preparation

Institutional Ethics Committee approved the placental tissue collection and written informed consent was obtained. All women were followed prospectively from enrolment until delivery. Different gestational placenta tissues from pregnant women of 1st trimester (N=6), 2nd trimester (N=6) and 3rd trimester (N=4) was collected and measured for relative miR-195 expression by qPCR. Human adipose tissues were collected from pregnant women with BMI over 30 (N=25 and 24 respectively) or with normal BMI (18-25) (N=22 for visceral and 20 for subcutaneous fat) and miR-195 expression was determined by qPCR. Moreover, human placental tissues were collected from women with pregnancy complicated by preeclampsia (N=14) and Intrauterine growth restriction (IUGR, N=12), and from normotensive pregnant women (N=17). The placental tissues collected were further used for quantitative PCR. Preeclampsia was defined as blood pressure >140/90 mm Hg on at least two consecutive measurements and maternal proteinuria of at least 300 mg/24 h and IUGR was defined as a foetus with estimated weight below the 10th percentile for its gestational age and abdominal circumference below the 2.5th percentile.

Cell and Placental Explants Culture

Human umbilical vein endothelial cells (HUVECs) were isolated and cultured in M199 medium as described previously (Bussolati et al, 2001). Experiments were performed on third or fourth passage HUVEC. First trimester placental tissues (6-9 weeks gestational age) were retrieved from normal pregnancies that had undergone elective termination. Placental villus tissue explants were prepared as described previously (Ahmad and Ahmed, 2004). Briefly, human placental villus explants were incubated under stimulation of test substances or hypoxia condition and collected for quantitative PCR of miR-195. To create hypoxic condition, 70-80% confluent HUEVCs or placental explants were cultured in an incubator with 1% O₂ and 5% CO₂ at 37° C. To mimic inflammatory condition, HUVECs or placental explants were stimulated in cyto-mix cocktail containing TNF-α (20 ng/ml), IFN-γ (20 ng/ml) and IL-1β (2 ng/ml).

miRNA Mimic and Inhibitor Against miR-195

Chemically synthesized double-stranded microRNA mimic and single-stranded inhibitor against miR-195 (mi-195 and anti-195) were purchased from Qiagen. The efficiency of these molecules was tested by qPCR using primer against miR-195 (FIG. 27 A).

HUVECs were trypsinized, and 1×10⁶ cells were electroporated with ≈0.6 ug mi-195, ≈3 ug anti-195 or equivalent control molecules using electroporation (Amaxa GmbH, Cologne, Germany) as described previously (Cudmore et al., 2007).

Adenovirus for miR-195

Adenovirus overexpressing eNOS constitutively activated form eNOS^(S1177D) ad-eNOS^(S1177D), was a gift from Prof. Ingrid Fleming (Johann Wolfgang Goethe University, Germany). The adenovirus overexpressing miR-195, ad-195, were purchased from Vector Biolabs (Philadelphia, Pa., USA) and the efficiency was tested using Qper (FIG. 27 B).

Ad-sFlt-1 Induced Mouse Preeclamptic Model

Adenovirus, ad-sFlt-1, was a gift from Prof. Richard Mulligan (Harvard Medical School, Boston, USA). The pregnant C57BL/6 mice were injected with 10⁹ PFU adenovirus, ad-CMV or ad-sFlt-1, at E 9.5 via tail vein injection. The sFlt-1 expression level in the circulation was measured using ELISA against Flt-1 and the mean artery pressure (MAP) was evaluated in the carotid artery at E 17.5 (FIG. 26). Placenta tissue from ad-CMV control virus (N=7) and ad-sFlt-1 virus (N=5) injected mice was collected and assayed for miR-195 expression using qPCR.

Reduced Uterine Perfusion Pressure (RUPP) Rat Model of Preeclampsia

Placenta samples of RUPP preeclamptic model were a gift from Dr. Fergus McCarthy (Cork University Maternity Hospital, Wilton, Cork, Ireland). The experimental procedure and the characterization of rat undergone RUPP surgery were described previously (McCarthy et al., 2011).

Real-Time Polymerase Chain Reaction

Sample preparation and real-time quantitative PCR was performed as described previously (Cudmore et al., 2007). Reverse transcription kit and primers against miR-195 were purchased from Quanta BioSciences.

Enzyme-Linked Immunosorbent Assay

Enzyme-linked immunosorbent assay (ELISA) kit for human PlGF was obtained from R&D Systems and performed according to the manufacturer's specifications.

Western Blotting

Total protein from HUVECs or animal tissue was lysed in RIPA buffer and assayed as previously described (Ahmad and Ahmed, 2004).

In Vitro Cell Viability and Proliferation Assay

HUVEC cells were electroporated with anti-195 or mi-195. After overnight recovery, transfected cells were trypsinized and plated into 96-well plate with 1×10⁴ per well under the vehicle or VEGF-A (20 ng/ml) treatment. After 48 h, these cells were proceeded to MTT assay using cell growth determination kit (Cat No. CDG1, Sigma-Aldrich). For cell proliferation assay, transfected cells were plated in 24-well plate with 4×10⁴ per well and stimulated with VEGF-A (20 ng/ml) or VGEF-E (20 ng/ml). After 48 h treatment, cells were trypsinized and the cell number per well was counted under microscope using a hemocytometer.

In Vitro Cell Adhesion Assay

HUVECs were electroporated with mi-195 or control mi-con. After 48 h, 2×10⁴ mi-195 or mi-con transfected cells were plated in the 2% gelatin coated 96-well plate and treated with VEGF-A (20 ng/ml) or VEGF-E (20 ng/ml) for 30 mins. Thereafter, cells were washed three times with PBS, stained with Calcein AM Fluorescent Dye and proceeded to fluorescent microscopy. The number of the adhesive cells per field under the 4× magnification was counted.

In Vitro Tube Formation Assay

Formation of capillary-like structures of HUVECs transfected with mi-195 or anti-195 or mi-195 co-infected with ad-eNOS^(S1177D) was determined on growth factor reduced Matrigel as previously described (Bussolati et al, 2001).

In Vitro Cell Migration Assay

HUEVC cells were electroporated with anti-195 or mi-195. After overnight recovery, the scratch was made in the centre of the transfected confluent cells in a 12- or 6-well plate. The width of the scratches was measured immediately at 0 h and 16-24 h after the scratches were generated. The cell migration distance was calculated by subtracting the width of scratches at 0 h and 16-24 h.

NO Gas Release Assay

Total NO in conditioned media was assayed as nitrite, the stable breakdown product of NO, using a Sievers NO chemiluminescence analyzer (Analytix, Sunderland, UK) as described previously (Ahmad et al., 2006). Briefly, HUVECs were infected with ad-con or ad-195 with MOI=100 and the condition medium were collected for NO measurement.

microRNA Target Luciferase Assay

The Homo sapiens cDNA containing untranslated region (UTR) of eNOS was purchased from Origene (Rockville, Md. 20850, USA) and the UTR region was subcloned into pMirTarget to generate eNOS-UTR-Luciferase (firefly) expression plasmid, pmiR-eNOS. The successful transfection of pmiR-eNOS in endothelial cells was validated by the expression of red fluorescent protein (RFP) (FIG. 28). The plasmid harbouring eNOS UTR mutant form of miR-195 binding site was generated using site-directed mutagenesis kit (Stratagene) with PCR primers containing the mutant site and the resulted plasmid was designated as pmiR-eNOSM. The primers used for PCR amplification were mNOS3-F (CTCTCAGGAGTAGAGTACCTGTAAAGGAGAATCTCTAAATCAAGT) and mNOS3-R (ACTTGATTTAGAGATTCTCCTTTACAGGTACTCTACTCCTGAGAG).

For microRNA target assay, HEK293 cells were transfected with pmiR-eNOS or pmiR-eNOSM together with mi-con or mi-195. The plasmid containing renilla luciferase gene was also transfected as the internal control. After overnight incubation, the relative firefly luciferase activity was measured and normalized to the renilla activity according to the manufacture's protocol of Dual-Luciferase® Reporter Assay System (E1910, Promega).

microRNA Target Prediction

The direct targets of miR-195 were predicted using online programs, microRNA.org (http://www.microrna.org/microrna/home.do), PicTar (http://pictar.mde-berlin.de/) Target Scan (http://www.targetscan.org/) RNAhybrid 2.2 and RNA22 microRNA target prediction.

MicroArray Profiling

HUVEC cells were transfected with mi-195 and the total RNA sample was collected for whole genome gene array analysis using Affymetrix genechip Human Gene 1.0 ST. The up-regulated and down-regulated genes upon mi-195 transfection are selected using a ±1.25-fold cut off.

Statistical Analysis

All data are expressed as mean+S.E.M. Statistical comparisons were performed using Student's t-Test or Mann-Whitney U test. Statistical significance was set at a value of p<0.05.

Results:

miR-195 Expression is Elevated in Severe Preeclampsia Patient and Animal Models, IUGR, Obesity Pregnant Women

Various microarray studies revealed that miR-195 expression was dysregulated in the placentas of preeclamptic women (Xu et al., 2014; Zhu et al., 2009; Hu et al., 2009). Thus we examined the expression pattern of miR-195 in different human tissues that are related to the pathogenesis of preeclampsia. First, the miR-195 expression in the placentas of pregnant women with different gestational age was determined by qPCR. The miR-195 expression in the 3^(rd) trimester placenta (N=4) was up-regulated by 12.5-fold and 8.9-fold respectively compared to 1^(st) (N=6) and 2^(nd) (N=6) trimester placenta (FIG. 22A). Furthermore, as obesity pregnant women pose a high risk to preeclampsia, we examined the miR-195 expression in the adipose tissues of obesity pregnant women. The miR-195 expression in the visceral (N=25) and subcutaneous fat (N=24) of obesity pregnant women was increased by 2.28-fold and 7.8-fold respectively compared to lean pregnant women (N=20-22) (FIGS. 22B and C). Although various microarray studies demonstrated the dysregulated expression of miR-195 in preeclampsia, the results from these studies are contradictive. More importantly, the placental samples used in these studies were collected from late gestational age of preeclampsia women range from 34.7 to 35.9 weeks. To investigate the miR-195 expression in more precisely defined early stage severe preeclampsia patients, the placental samples from preeclampsia women with an average gestational age of 29.7 weeks were collected and examined for miR-195 expression by qPCR. Quantitative PCR revealed that miR-195 expression in the preeclamptic placenta (N=14) and IUGR placenta (N=12) was increased by 10.9-fold and 2.6-fold respectively compared to gestation age matched control normotensive placenta (N=17) (FIG. 22D).

To further confirm the up-regulation of miR-195 in preeclampsia, the expression of miR-195 was examined in two animal models of preeclampsia. The pregnant mice receiving ad-sFlt-1 adenovirus injection (N=5) exhibited significant increased placental miR-195 level (FIG. 22E) as well as elevated sFlt-1 expression and mean artery pressure compared to ad-CMV control virus injected mice (N=7) (FIG. 26). Moreover, the miR-195 expression in placenta of pregnant Sprague Dawley rats that undergone reduced uterine perfusion pressure surgery (N=17) was also increased by 7.7-fold compared to normal pregnant rat (N=12, FIG. 22F). Taken together, these data suggest that miR-195 elevation is associated with pathogenesis of preeclampsia.

Hypoxia and Inflammatory Cytokines Elevates miR-195 Expression

Preeclamptic placenta is associated with hypoxia, inflammation condition as well as the elevation of VEGF and FGF-2 growth factors (Hunter et al., 2000; Ozkan et al., 2008), thus the miR-195 expression in the endothelial cells and placental explants under hypoxia and inflammation stimulation was determined by qPCR. Stimulation of mixed inflammatory cytokines in HUVEC cells increased miR-195 by approximate 43% (FIG. 22G). Furthermore, the combination of hypoxia and inflammatory cytokine mixture stimulation increased miR-195 expression by 138% and 48% in HUVECs and placental explants respectively (FIGS. 22H and I). These data confirmed that miR-195 expression is regulated by the pathological conditions that associated with preeclamptic placenta.

MiR-195 Modulates PlGF Expression in Endothelial Cells

The release of anti-angiogenic factors, sFlt-1 and sEng, and the inhibition of placental growth factor (PlGF) expression are the main cause of preeclampsia (Powe et al., 2011; Ahmad and Ahmed, 2004), therefore we examined whether miR-195 modulates sFlt-1, sEng or PlGF expression in endothelial cells. HUVECs were transfected with mi-195 to over-express miR-195 (FIG. 27) and the sFlt-1, sEng and PlGF release was examined by ELISA. Although overexpression of miR-195 in HUVECs did not change sFlt-1 and sEng expression, the PlGF level was significantly reduced under both vehicle and VEGF stimulation (FIG. 23A). As a result, the ratio of sFlt-1/PlGF was increased. These data further support the concept that miR-195 upregulation may contribute to the pathogenesis of preeclampsia.

MiR-195 Inhibits Endothelial Cell Proliferation, Viability, Adhesion and In Vitro Tube Formation, but Promotes Cell Migration

Since the impaired endothelium is the main cause of preeclampsia, we tested whether miR-195 modulates endothelial cell functions. HUVECs were transfected with synthetic mimic (mi-195) and the cell proliferation assay was performed. Overexpression of miR-195 decreased cell number by 35% to 62% compared to control under vehicle, VEGF-A or VEGF-E stimulation (FIG. 23B). Moreover, MTT assay in the HUVECs transfected with mi-195 further confirmed that miR-195 overexpression decreased cell viability by 35% or 31% under vehicle or VEGF stimulation respectively (FIG. 23C).

The effect of miR-195 overexpression in endothelial cell adhesion was also tested. The adhesive ability was dramatically decreased in the mi-195 transfected cells regardless the stimulation of VEGF-A or VEGF-E. Cell counting confirmed an approximate 70% reduction of adhesive cells in the mi-195 transfected HUVECs under vehicle, VEGF-A or VEGF-E stimulation compared to mi-con transfected cells (FIG. 23D).

Since miR-195 inhibits angiogenesis in tumor cells, we speculated that miR-195 also inhibits angiogenesis in placental endothelial cells to contribute to the pathogenesis of preeclampsia. HUVECs transfected with mi-195 exhibited decreased tube formation on Matrigel under vehicle, VEGF-A or VEGF-E stimulation (FIG. 23E). Quantitative analysis revealed a 40% reduction in the tube formation of mi-195 transfected cells under vehicle condition and 40% to 84% reduction under VEGF-A or VEGF-E stimulation.

Moreover, the role of miR-195 in endothelial cell migration was determined by scratch assay. HUVECs transfected with anti-195 showed 11% to 26% decrease of migration ability compared to anti-con transfected control cells under vehicle or VGEF stimulation (FIG. 24A). Conversely, Overexpression of miR-195 in HUVECs significantly increased cell migration ability by approximate 1.25-fold under vehicle or VEGF-A stimulation (FIG. 24B).

MiR-195 Directly Targets eNOS in Endothelial Cells

To identify the direct targets of miR-195, gene expression microarray was performed using RNA samples from mi-195 and mi-con transfected HUVEC cells. The 10 up-regulated and 12 down-regulated genes upon miR-152 over-expression were selected with ±1.25-fold cut off. These expression altered genes have broad functions on vascular remodeling, cell adhesion, mobility and angiogenesis. Moreover, the down-regulated genes were further analyzed using online prediction tools to confirm the possible direct targets of miR-195 by sequence alignment. Finally, four down-regulated genes were selected for candidates of miR-195 direct target.

Among these direct targets, eNOS was the most important and well characterized in the literature. First, eNOS was predicted to be miR-195 direct target by the online prediction tools in various animal species (FIG. 25A). Furthermore, microRNA target assay proved that transfection of mi-195 significantly inhibited luciferase activity in the pmiR-eNOS transfected HEK293 cells, but not in the eNOS UTR mutant plasmid, pmiR-eNOSM, transfected cells (FIG. 25B; FIG. 28). The luciferase assay data was further supported by the evidence that eNOS mRNA and protein levels were decreased in the HUVECs transfected with mi-195. Quantitative PCR revealed a 22% decrease in mi-195 transfected HUVECs (FIG. 25C) and western blot using antibodies against total eNOS and phosphor-eNOS demonstrated an approximate 55% reduction of total eNOS and 24% to 56% reduction of phosphor-eNOS in mi-195 transfected cells (FIGS. 25D and E). More importantly, the release of NO gas in the HUVECs transfected with mi-195 was reduced by 27% compared to mi-con transfected cells (FIG. 25F). Finally, in order to validate that eNOS is the downstream effector of miR-195 mediated endothelial dysfunction, we tested whether overexpression of eNOS could rescue the mi-195 mediated inhibition of angiogenesis. As expected, miR-195 overexpression decreased spontaneously tube formation, while overexpression of eNOS^(S1177D) completely recovered mi-195 mediated inhibition of tube-like structure in HUVEC cells (FIGS. 25G and H).

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1. A method of treating preeclampsia, fetal growth restriction (FGR or IUGR), obesity in pregnancy, post-partum cardiomyopathy (heart failure in mothers), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet macrodegeneration and other disorders in a subject where angiogenesis is aberrant either diminished or exacerbated, comprising modulating the activity of microRNA (miRNA).
 2. A method according to claim 1, wherein the miRNA is selected from miR-122, miR-374b, miR-152 and miR-195, or a functional fragment or homologue thereof.
 3. A method according to claim 1, comprising one or more of increasing miR-122, increasing miR374b, decreasing miR-152 or decreasing miR-195 activity in a subject with preeclampsia, fetal growth restriction (FGR or IUGR), obesity in pregnancy, post-partum cardiomyopathy (heart failure in mothers), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet macrodegeneration and other disorders where angiogenesis is aberrant either diminished or exacerbated.
 4. A method according to claim 1, comprising increasing expression of an miRNA or a combination thereof or administering an miRNA or a functional fragment or homologue or a combination thereof or functional fragments or homologues.
 5. A method according to claim 1, comprising decreasing activity of the miRNA by administering an inhibitor of the miRNA or the combination of miRNA inhibitors.
 6. An miRNA, an miRNA modulator or a combination thereof or functional fragments or homologues thereof for use in the method of claim
 1. 7. An miRNA according to claim 6, wherein the modulator is an miRNA, wherein the miRNA is selected from miR-122 and miR-374b or a combination thereof or functional fragments or homologues thereof, or the modulator is an miRNA inhibitor selected from an inhibitor of miR-152 or miR-195, or a combination thereof.
 8. The method of claim 1, wherein angiogenesis is modulated by modulating the activity of miR-152, miR-195, miR-122 or miR-374b.
 9. A pharmaceutical composition, comprising two or more of miR-122, miR-374b, an inhibitor of miR-152 and inhibitor of miR-195, or functional fragments or homologues, or pharmaceutically acceptable salts thereof.
 10. The method of claim 1, wherein miR-122 or miR-374b modulates sFlt-1 in a disease where sFlt-1 is elevated.
 11. The method of claim 1, wherein the activity of miRNA is modulated by activators or inhibitors of miR-122, miR-374b, miR-152 or miR-195 miRNA target proteins.
 12. Activators or inhibitors according to claim 11, wherein the activator or inhibitor is selected from sFlt-1, ITGA5 and eNOS.
 13. A method of predicting or diagnosing onset of preeclampsia or post-partum cardiomyopathy (heart failure in mothers), cancer and diabetic retinopathy, cardiomyopathy, myocardial infarction, wet macrodegeneration, comprising the use of MiR-122, miR374b, miR-152 or miR-195, in a sample from a subject.
 14. A method according to claim 12, wherein the sample is saliva, serum, plasma, urine or a body tissue isolated from the body.
 15. The pharmaceutical composition according to claim 9, wherein miR-122, miR-374b, an inhibitor of miR-152 and inhibitor of miR-195, or functional fragments or homologues, or pharmaceutically acceptable salts thereof comprise chemical modifications.
 16. The method according to claim 13, wherein fragments of activators or inhibitors of miR-122, miR-374b, miR-152 or miR-195 miRNA target proteins is/are used for diagnosis. 